Since diarrhea has many possible causes, your doctor will ask you about your personal circumstances. Recent travel history or exposure to family members with similar symptoms might suggest an infection.
Your doctor will review your symptoms and exam you. If you have severe symptoms, your doctor also may ask for a stool sample. The specimen will be analyzed in a laboratory to look for infectious causes.
Symptoms of diarrhea are usually most severe during the first 24 hours. Although some episodes of acute diarrhea last as long as 14 days, most go away within three to seven days.